Saint Nicholas Cathedral (officially Cathédrale Notre-Dame-Immaculée) is the cathedral of the Roman Catholic Archdiocese of Monaco, where many of the Grimaldis were buried, including Grace Kelly and more recently, Rainier III.
The cathedral was built in 1875-1903 and consecrated in 1911, and is on the site of the first parish church in Monaco built in 1252 and dedicated to St. Nicholas. Of note are the retable (circa 1500) to the right of the transept, the Great Altar and the Episcopal throne in white Carrara marble.
Pontifical services take place on the major religious festivals such as the Feast of Sainte Dévote (27 January) and the National holiday (19 November). On feast days and during religious music concerts, one can hear the magnificent four-keyboard organ, inaugurated in 1976.
References:Duino Castle was built by the Wallsee family in 1389 on the cliffs overlooking the Gulf of Trieste. It replaced an older castle from the 11th century. Over time, the Wallsee family disappeared and the castle, after having been used as a prison, became the residence of the Luogar and Hofer.
At the end of the 19th century it became the property of Prince Alexander von Thurn und Taxis from the Czech branch of the House of Thurn and Taxis. It remains with the family to this day with his great-grandson Prince Carlo Alessandro della Torre e Tasso, Duke of Castel Duino the current owner. The castle has been opened to the public as a museum and park.